(Cover) - EN Showbiz - Selena Gomez was hospitalised because she was "very malnourished" and exhausted.

The 18-year-old singer-and-actress was rushed to hospital last Thursday following an appearance on the Tonight Show with Jay Leno. She felt sick and developed severe headaches, and underwent tests in a Los Angeles medical centre.

The star was back to her best yesterday as she started promotion for her movie Monte Carlo. She appeared at Santa Monica Palace and assured fans she's now feeling well.

"I'm fine. I was just very malnourished," she explained. "I was low on iron and exhausted."

The event was rescheduled as it was supposed to take place on Friday but Selena was ill. She took the time to thank fans for attending the new date, insisting it meant a great deal to her.

"I want to thank you so much for coming," she told the crowd, according to People. "If you guys came on Friday, I'm so sorry that I couldn't be here... I love you guys very much."

Around 500 young people gathered at the mall to see their idol. She laughed off questions about whether boyfriend Justin Bieber had supported her through her health scare, only saying many of her loved ones had been there for her.

"I got very lovely things from my family and friends," she giggled.

Earlier in the day Selena took to her Twitter and Facebook pages to thank fans for their concern and reassure them she was fighting fit again.

"Just wanted to say thank you so much for all of the get well wishes. I love you guys so much," she wrote. (C) Cover Media